This invention relates to a multistage conveying system comprising
(A) a loading unit for receiving a material, in particular loose material, to be conveyed from a lower level place of delivery, such as a ship's hold or the like, to a higher level depositing facility,
(B) a steeply, in particular a substantially vertically lifting elevator unit, to the lower end of which material is transferred from the loading unit,
(C) a depositing transom (or jib) unit for taking up material from the upper end of the elevator unit and transferred to the depositing facility
each of the said units having a central longitudinal axis; and
the elevator unit comprises
(1) an endless elevator belt having an outer elevator belt face and and inner elevator belt face, and
(2) a row of material-receiving receptacles, borne between the elevator belt faces, and adapted for being loaded with the material via the outer elevator belt face, the endless elevator belt being adapted for moving through an inner ascending reach and an outer descending reach;
the loading unit, elevator unit and transom unit comprising jointly
(a) an endless standard belt having an outer standard belt side and an inner standard belt side, and being adapted for moving through an upper and inner ascending standard belt reach and a lower and outer descending standard belt reach,
the said standard belt sealingly covering the outer elevator belt face while passing through the ascending reach in the elevator unit;
(b) angle-adjusting means associated with the elevator unit and the transom unit and adapted for adjusting an angle between the central longitudinal axes of the elevator unit and the transom unit, these angle-adjusting means comprising a position-setting device having an adjustable transverse length and being articulatedly connected with each of the elevator unit and transom unit.
A conveying system of this kind has been described in German Offenlegungsschrift No. 29 30 957, which is an addition to the German patent application No. 27 17 100.2.
More in detail, there is described a band (or belt strap) conveyor for conveying loose material over long distances or great heights, which conveyor consists of an endless conveyor belt supported by rollers which comprises one or several vertical conveyance sectors arranged along the entire conveyor length, in which sectors the transported material is held in place by means of cover belts.
It is a main feature of this German published application that in addition to the vertical conveying sectors, or in their place, one or several nearly horizontally ascending or inclined curved conveyor sectors are employed, and, in one embodiment, conveyance is effected by the upper reach of a conveyor belt, which is first given a trough-shaped cross-section by employing trio groups each of three rollers aligned in a conventional manner, and during advancing conveyance, the lateral slopes of the trough are gradually raised toward a vertical position by a corresponding continously steeper positioning of the two lateral rollers of each successive trio of rollers until they from an angle of 90.degree. with the central roller supporting the bottom of the trough. After accomplished trough-formation with the two lateral rollers of the trio groups along the advancing reach of the cover belt the latter is guided overlappingly over the trough-shaped upper reach of the conveyor belt, and the resulting composite belt is held together by supporting rollers engaging the belt on both sides.
Further features of the system according to this published application comprise the possibility of spiralling the composite belt, which, however, does not concern the present invention.
In a further addition to the last-mentioned German parent application No. 27 17 100.2, which has been published as Offenlegungsschrift No. 30 05 452, there is solved the problem of enabling continued movement of the conveyor, after passthrough a vertical conveying sector, on the next higher conveyance level, at a random angle with the direction in which the lower level supply reach extends. Apart from this feature the above-made remarks concerning German Offenlegungsschrift No. 29 30 957 apply likewise.
The maintenance of the covering of the upper reach of the belt strap conveyor belt by means of the upper reach of the covering band over at least an essential part of its length is a common feature of this group of systems.
Covering of the transom unit for granulated or larger-piece loose material is not required as a rule, and may even be undesirable, as it disturbs the visual control of the conveyance of material in particular in a reach of changing or reversing the direction of conveyance, quite apart from the unnecessary additional structure this would demand.
The conversion of the two belts to trough-shaped cross section ("Aufmuldung") must be considered a further drawback as this does not only require additional work, but also considerably increases the wear of the belts by the constantly re-occurring bending of the marginal belt zones on both sides of the belt.
Furthermore, German Offenlegungsschrift No. 31 45 104 discloses a direction-reversing station comprising vertical and horizontal conveying branch lines, which station consists of an undulated-edge band belt and of a cover belt closing off the former belt.
There are formed at least two conveying sectors one of which is of constant, stationary positioning or of changeable position, relative to the other one. A supporting framework is provided with a supporting roller combination for the conveyor belt as well as for the cover belt which takes into account the angle of the belt reversal.
A critical feature of this system is the formation of carrying stations having adjustable, changeable distances between the shafts of the supporting rollers for the undulated-edge band belt and, arranged on both sides of the first-mentioned roller, the two supporting rollers for the cover belt region.
The distance between the cover belt and the undulated-edge band belt is so adjusted, in principle, that no force-transmitting direct contact is possible between the two belts. Each supporting point comprises three supporting rollers of each of which the first and the second supporting roller are in coaxial arrangement and associated, as a rule, with the cover belt, while the third supporting roller of each trio is associated with the undulated-edge band belt. In the case of the illustrated example, the supporting rollers relating to the cover belt are of changeable positioning, while the supporting rollers relating to the undulated-edge band belt are in fixed position.
Means for adjusting the distancing between the roller shafts engage the movably positioned support means.
The three supporting rollers of each roller group thus have their three axes arranged in a common radial plane, taken with respect to the belt-direction reversal, i.e., the two short rollers support on both sides the edges of the cover belt, while the long roller supports the undulated-edge belt over its entire width.
Means provided for adjusting the positioning of the movably supported rollers comprise a weight-loaded pulling (or tensioning) station acting in the direction of the deflection of a transom unit. However, this station can only adjust the angle of the transom unit with regard to the vertical elevator unit in a movement that does not comprise the spreading or reverse closing of two legs, but the angle of relative positioning of two units is adjusted merely by moving a single leg. This has the drawback of reducing the possibilities of manipulating the conveyor system.